U.S. patent number 10,006,431 [Application Number 15/641,345] was granted by the patent office on 2018-06-26 for semiconductor apparatus.
This patent grant is currently assigned to FUJI ELECTRIC CO., LTD.. The grantee listed for this patent is FUJI ELECTRIC CO., LTD.. Invention is credited to Shigemi Miyazawa.
United States Patent |
10,006,431 |
Miyazawa |
June 26, 2018 |
Semiconductor apparatus
Abstract
A semiconductor apparatus is provided, comprising a power
semiconductor element which is connected between a first terminal
on a high-potential side and a second terminal on a low-potential
side and is controlled to be turned on or off according to a gate
potential, a cut-off condition detection section which detects
whether or not a control signal that is input from a control
terminal and controls the power semiconductor element satisfies a
predetermined cut-off condition, and a cut-off circuit which
controls the gate potential of the power semiconductor element to
be an OFF potential in response to the cut-off condition detection
section detecting that the cut-off condition is satisfied, and the
cut-off condition detection section has an input terminal connected
to the first terminal and the control terminal, and uses an
electrical signal input from the input terminal as a power
source.
Inventors: |
Miyazawa; Shigemi (Matsumoto,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
FUJI ELECTRIC CO., LTD. |
Kanagawa |
N/A |
JP |
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Assignee: |
FUJI ELECTRIC CO., LTD.
(Kanagawa, JP)
|
Family
ID: |
60940898 |
Appl.
No.: |
15/641,345 |
Filed: |
July 5, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180017033 A1 |
Jan 18, 2018 |
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Foreign Application Priority Data
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Jul 12, 2016 [JP] |
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2016-137885 |
Nov 9, 2016 [JP] |
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2016-218920 |
Jun 19, 2017 [JP] |
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2017-119831 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02P
3/0435 (20130101); F02P 3/053 (20130101); H03K
17/06 (20130101); H03K 17/042 (20130101); H03K
17/302 (20130101); H01L 29/7395 (20130101); H03K
2217/0081 (20130101); F02P 9/002 (20130101); H01L
29/7802 (20130101); H03K 2017/066 (20130101); F02P
3/0554 (20130101) |
Current International
Class: |
H01T
15/00 (20060101); F02P 3/04 (20060101); H03K
17/30 (20060101); H01L 29/78 (20060101); H01L
29/739 (20060101) |
Field of
Search: |
;123/644,630,651,143B,146.5A,406.66 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2009-284420 |
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Dec 2009 |
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JP |
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2015-177328 |
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Oct 2015 |
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JP |
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Primary Examiner: Owens; Douglas W
Assistant Examiner: Chan; Wei
Claims
What is claimed is:
1. A semiconductor apparatus, comprising: a power semiconductor
element which is connected between a first terminal on a
high-potential side and a second terminal on a low-potential side
and is controlled to be turned on or off according to a gate
potential; a cut-off condition detection section which detects
whether or not a control signal that is input from a control
terminal and controls the power semiconductor element satisfies a
predetermined cut-off condition; a cut-off circuit which controls
the gate potential of the power semiconductor element to be an OFF
potential in response to the cut-off condition detection section
detecting that the cut-off condition is satisfied, wherein the
cut-off condition detection section has an input terminal which is
connected to the first terminal and the control terminal and uses
an electrical signal input from the input terminal as a power
source; a first rectifying element which is connected between the
control terminal and the input terminal of the cut-off condition
detection section; and a second rectifying element which is
connected between the first terminal and the input terminal of the
cut-off condition detection section; wherein the cut-off condition
detection section has: a detection section which detects whether or
not the control signal exceeds a predetermined threshold, and a
signal output section which outputs a cut-off control signal that
controls the cut-off circuit according to a detection result of the
detection section.
2. A semiconductor apparatus, comprising: a power semiconductor
element which is connected between a first terminal on a
high-potential side and a second terminal on a low-potential side
and is controlled to be turned on or off according to a gate
potential; a cut-off condition detection section which detects
whether or not a control signal that is input from a control
terminal and controls the power semiconductor element satisfies a
predetermined cut-off condition; a cut-off circuit which controls
the gate potential of the power semiconductor element to be an OFF
potential in response to the cut-off condition detection section
detecting that the cut-off condition is satisfied, wherein the
cut-off condition detection section has an input terminal which is
connected to the first terminal and a gate terminal of the power
semiconductor element and, is connected to the control terminal via
a resistive element, and uses an electrical signal input from the
input terminal as a power source; a first rectifying element which
is connected between the resistive element and the input terminal
of the cut-off condition detection section; and a second rectifying
element which is connected between the first terminal and the input
terminal of the cut-off condition detection section; wherein the
cut-off condition detection section has: a detection section which
detects whether or not the control signal exceeds a predetermined
threshold, and a signal output section which outputs a cut-off
circuit control signal that controls the cut-off circuit according
to a detection result of the detection section.
3. The semiconductor apparatus according to claim 2, wherein the
resistive element is a resistance or a switch element.
4. The semiconductor apparatus according to claim 1, wherein the
signal output section is connected to the first rectifying element
and the second rectifying element and uses an electrical signal
input from the first terminal and the control terminal as a power
source.
5. The semiconductor apparatus according to claim 1, wherein a
resistance or a switch element is connected between the first
terminal and the second rectifying element.
6. The semiconductor apparatus according to claim 1, wherein the
cut-off circuit electrically connects a gate and an emitter of the
power semiconductor element to set the gate of the power
semiconductor element to an OFF potential.
7. The semiconductor apparatus according to claim 1, wherein the
power semiconductor element is an IGBT (insulated gate bipolar
transistor) or a vertical MOSFET.
8. The semiconductor apparatus according to claim 1, further
comprising a delay circuit which is provided between the cut-off
condition detection section and the cut-off circuit and delays a
signal transmitted to the cut-off circuit by the cut-off condition
detection section.
9. The semiconductor apparatus according to claim 1, wherein the
semiconductor apparatus is an igniter which controls currents
flowing through an ignition coil according to a control signal from
outside.
10. The semiconductor apparatus according to claim 2, wherein the
signal output section is connected to the first rectifying element
and the second rectifying element and uses an electrical signal
input from the first terminal and the control terminal as a power
source.
11. The semiconductor apparatus according to claim 2, wherein a
resistance or a switch element is connected between the first
terminal and the second rectifying element.
12. The semiconductor apparatus according to claim 2, wherein the
cut-off circuit electrically connects a gate and an emitter of the
power semiconductor element to set the gate of the power
semiconductor element to an OFF potential.
13. The semiconductor apparatus according to claim 2, wherein the
power semiconductor element is an IGBT (insulated gate bipolar
transistor) or a vertical MOSFET.
14. The semiconductor apparatus according to claim 2, further
comprising a delay circuit which is provided between the cut-off
condition detection section and the cut-off circuit, and delays a
signal transmitted to the cut-off circuit by the cut-off condition
detection section.
15. The semiconductor apparatus according to claim 2, wherein the
semiconductor apparatus is an igniter which controls currents
flowing through an ignition coil according to a control signal from
outside.
Description
The contents of the following Japanese patent applications are
incorporated herein by reference:
NO. 2016-137885 filed on Jul. 12, 2016,
NO. 2016-218920 filed on Nov. 9, 2016, and.
NO. 2017-119831 filed on Jun. 19, 2017.
BACKGROUND
1. Technical Field
The present invention relates to semiconductor apparatuses.
2. Related Art
Conventionally, a power semiconductor device dealing with large
power has been known as a semiconductor apparatus used for an
ignition and the like of an internal combustion engine (for
example, refer to Patent Document 1). It is desirable that a
circuit to drive such a power semiconductor device can prevent a
malfunction where the power semiconductor device is still set to an
ON state even though a cut-off signal to set the power
semiconductor device to an OFF state has been received.
[Patent Document 1] Japanese Patent Application Publication NO.
2009-284420
If such a drive circuit of the power semiconductor device continues
operating in a state where the malfunction occurs and the
abnormality remains, defects and the like may occur not only in the
drive circuit but also in the internal combustion engine and the
like connected to the drive circuit. Therefore, it has been desired
that the drive circuit has a function to surely cut off the power
semiconductor device when the cut-off signal is input.
SUMMARY
Here, a purpose of one aspect of the technological innovation
included in the present specification is to provide a semiconductor
apparatus which can solve the above-described problem. This purpose
is achieved by combinations of characteristics according to the
claims. That is, in a first aspect of the present invention, a
semiconductor apparatus is provided, the semiconductor apparatus
comprising a power semiconductor element which is connected between
a first terminal on a high-potential side and a second terminal on
a low-potential side and is controlled to be turned on or off
according to a gate potential, a cut-off condition detection
section which detects whether or not a control signal that is input
from a control terminal and controls the power semiconductor
element satisfies a predetermined cut-off condition, and a cut-off
circuit which controls the gate potential of the power
semiconductor element to be an OFF potential in response to the
cut-off condition detection section detecting that the cut-off
condition is satisfied, and the cut-off condition detection section
has an input terminal connected to the first terminal and the
control terminal and uses an electrical signal input from the input
terminal as a power source.
The summary clause does not necessarily describe all necessary
features of the embodiments of the present invention. The present
invention may also be a sub-combination of the features described
above.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an exemplary configuration of an ignition apparatus
1000 according to the present embodiment.
FIG. 2 shows a first example of operation waveforms of each section
of a semiconductor apparatus 100 according to the present
embodiment.
FIG. 3 shows an exemplary configuration of an ignition apparatus
2000 according to the present embodiment.
FIG. 4 shows an exemplary configuration of a detection section 132
according to the present embodiment.
FIG. 5 shows one example of operation waveforms of each section of
the detection section 132 according to the present embodiment.
FIG. 6 shows examples of operation waveforms of each section of a
semiconductor apparatus 200 according to the present
embodiment.
FIG. 7 shows a first modification example of the ignition apparatus
2000 according to the present embodiment.
FIG. 8 shows a second example of the operation waveforms of each
section of the semiconductor apparatus 100 according to the present
embodiment.
FIG. 9 shows one example of enlarged waveforms of the second
example of the operation waveforms shown in FIG. 8.
FIG. 10 shows a second modification example of the ignition
apparatus 2000 according to the present embodiment.
FIG. 11 shows one example of operation waveforms of each section of
the semiconductor apparatus 200 of the second modification
example.
FIG. 12 shows a third modification example of the ignition
apparatus 2000 according to the present embodiment.
FIG. 13 shows one example of operation waveforms of each section of
the semiconductor apparatus 200 of the third modification
example.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
The embodiments do not limit the invention according to the claims,
and all the combinations of the features described in the
embodiments are not necessarily essential to means provided by
aspects of the invention.
FIG. 1 shows an exemplary configuration of an ignition apparatus
1000 according to the present embodiment. The ignition apparatus
1000 ignites an ignition plug used for an internal combustion
engine and the like of automobiles and the like. In the present
embodiment, an example where the ignition apparatus 1000 is
equipped in an engine of an automobile will be described. The
ignition apparatus 1000 comprises a control signal generation
section 10, an ignition plug 20, an ignition coil 30, a power
source 40, and a semiconductor apparatus 100.
The control signal generation section 10 generates a switching
control signal which controls switching between ON and OFF of the
semiconductor apparatus 100. For example, the control signal
generation section 10 is a part or the whole of an engine control
unit (ECU) of an automobile where the ignition apparatus 1000 is
equipped. The control signal generation section 10 supplies the
generated control signal to the semiconductor apparatus 100. By
supplying to the semiconductor apparatus 100 the control signal by
the control signal generation section 10, the ignition apparatus
1000 starts an igniting operation of the ignition plug 20.
The ignition plug 20 electrically generates sparks by discharges.
For example, the ignition plug 20 discharges by an applied voltage
which is equal to or greater than about 10 kV. As one example, the
ignition plug 20 is provided in an internal combustion engine, and
in this case, the ignition plug 20 ignites combustible gas such as
mixed gas and the like in the combustion chamber. The ignition plug
20 is, for example, provided in a through hole which penetrates
from outside the cylinder to the combustion chamber inside the
cylinder, and is fixed so as to seal the through hole. In this
case, one end of the ignition plug 20 is exposed inside the
combustion chamber and the other end receives an electrical signal
from the outside of the cylinder.
The ignition coil 30 supplies an electrical signal to the ignition
plug 20. The ignition coil 30 supplies a high voltage as the
electrical signal to cause the ignition plug 20 to discharge. The
ignition coil 30 may function as a transformer and is an ignition
coil having a primary coil 32 and a secondary coil 34, for example.
One end of the primary coil 32 and one end of the secondary coil 34
are electrically connected. The primary coil 32 has a smaller
number of turns of winding than the secondary coil 34 and shares a
core with the secondary coil 34. The secondary coil 34 generates an
electromotive force (a mutual induced electromotive force)
according to an electromotive force generated in the primary coil
32. The secondary coil 34 is connected to the ignition plug 20 on
the other end and supplies the generated electromotive force to the
ignition plug 20 to cause the ignition plug 20 to discharge.
A power source 40 supplies a voltage to the ignition coil 30. For
example, the power source 40 supplies a predetermined constant
voltage Vb (as one example, 14V) to one end of the primary coil 32
and one end of the secondary coil 34. The power source 40 is a
battery of automobiles as one example.
The semiconductor apparatus 100 switches between conduction (ON)
and non-conduction (OFF) between the other end of the primary coil
32 of the ignition coil 30 and a reference potential according to a
control signal supplied from the control signal generation section
10. For example, the semiconductor apparatus 100 switches to
conduction between the primary coil 32 and the reference potential
in response to the control signal being a high potential (an ON
potential), and switches to non-conduction between the primary coil
32 and the reference potential in response to the control signal
being in a low potential (an OFF potential).
Here, the reference potential may be a reference potential in a
control system of an automobile, or may be a reference potential
corresponding to the semiconductor apparatus 100 in an automobile.
The reference potential may be a low potential to turn the
semiconductor apparatus 100 off, and is 0V as one example. The
semiconductor apparatus 100 comprises a control terminal 102, a
first terminal 104, a second terminal 106, a power semiconductor
element 110, a cut-off circuit 120, a cut-off condition detection
section 130, a resistance 150, a resistance 160, and a Zener diode
170.
The control terminal 102 inputs a control signal which controls the
power semiconductor element 110. The control terminal 102 is
connected to the control signal generation section 10 and receives
the control signal. The first terminal 104 is connected to the
power source 40 via the ignition coil 30. The second terminal 106
is connected to the reference potential. That is, the first
terminal 104 is a terminal on a high-potential side compared to the
second terminal 106, and the second terminal 106 is a terminal on a
low-potential side compared to the first terminal 104.
In the power semiconductor element 110, the gate potential is
controlled according to the control signal. The power semiconductor
element 110 includes a gate terminal (G), a collector terminal (C),
and an emitter terminal (E), and electrically connects or
disconnects between the collector terminal and the emitter terminal
according to the control signal input into the gate terminal. The
power semiconductor element 110 is connected between the first
terminal 104 on the high-potential side and the second terminal 106
on the low-potential side and is controlled to be turned on or off
according to the gate potential. The power semiconductor element
110 is an insulated gate bipolar transistor (IGBT) as one example.
Also, the power semiconductor element 110 may be a MOSFET.
The power semiconductor element 110 has a withstand voltage up to
several hundreds of V, as one example. For example, the power
semiconductor element 110 is a vertical device in which a collector
electrode is formed on a first surface side of a substrate and a
gate electrode and an emitter electrode are formed on a second
surface side which is opposite to the first surface. Also, the
power semiconductor element 110 may be a vertical MOSFET. As one
example, the emitter terminal of the power semiconductor element
110 is connected to the reference potential. Also, the collector
terminal is connected to the other end of the primary coil 32. In
the present exemplary embodiment, an example is described, where
the power semiconductor element 110 is an n channel type IGBT which
electrically connects between the collector terminal and the
emitter terminal in response to the control signal becoming the ON
potential.
The cut-off circuit 120 is connected between the gate terminal of
the power semiconductor element 110 and the reference potential. As
one example, the cut-off circuit 120 is an FET to control ON/OFF
states between a drain terminal and a source terminal according to
the gate potential. In the cut-off circuit 120, the drain terminal
is connected to the gate terminal of the power semiconductor
element 110 and the source terminal is connected to the reference
potential, and the cut-off circuit 120 switches whether or not to
supply the control signal input from the control terminal 102 to
the gate terminal of the power semiconductor element 110.
In other words, in the cut-off circuit 120, the drain terminal is
connected to the gate terminal of the power semiconductor element
110 and the source terminal is connected to the emitter terminal of
the power semiconductor element 110, and the cut-off circuit 120
electrically connects the gate terminal and the emitter terminal of
the power semiconductor element 110 to switch whether or not to set
the gate of the power semiconductor element 110 to the OFF
potential. As one example, the cut-off circuit 120 is a
normally-off switch element to electrically connect between the
drain terminal and the source terminal in response to the gate
terminal becoming the high potential. In this case, it is desirable
that the cut-off circuit 120 is an n channel type MOSFET.
The cut-off condition detection section 130 detects whether or not
a control signal that is input from the control terminal 102 and
controls the power semiconductor element 110 satisfies a
predetermined cut-off condition. The cut-off condition detection
section 130 may detect whether or not the control signal uses a
predetermined threshold and satisfies the cut-off condition. The
cut-off condition detection section 130 has a detection section 132
and a signal output section 134.
The detection section 132 detects whether or not the control signal
exceeds the predetermined threshold. For example, the detection
section 132 determines that the cut-off condition is satisfied in
response to a control signal Vin which turns the power
semiconductor element 110 on becoming smaller than a threshold
Vthin (2V, as one example). The detection section 132 supplies a
detection result to the signal output section 134.
The signal output section 134 outputs a cut-off circuit control
signal, which controls the cut-off circuit 120, according to the
detection result of the detection section 132. The signal output
section 134 outputs a cut-off circuit control signal, which turns
the cut-off circuit 120 on, according to a detection result showing
that the control signal satisfies the cut-off condition. Also, the
signal output section 134 outputs a cut-off circuit control signal,
which turns the cut-off circuit 120 off, according to a detection
result showing that the control signal does not satisfy the cut-off
condition.
As one example, the signal output section 134 is an inverter. The
signal output section 134 operates using an electrical signal input
from the first terminal 104 as a power source, and inverts the
detection result of the detection section 132 and outputs the
inverted result. The signal output section 134 is connected to the
cut-off circuit 120 and supplies the cut-off circuit control signal
to the cut-off circuit 120. That is, the cut-off circuit 120
controls the gate potential of the power semiconductor element 110
to be the OFF potential according to the detection where the
cut-off condition detection section 130 satisfies the cut-off
condition.
The resistance 150 is provided between the first terminal 104 and a
power source terminal on the high-potential side of the signal
output section 134, and supplies an electrical signal input from
the first terminal 104 to the signal output section 134 as the
power source. Note that the electrical signal input from the first
terminal 104 varies according to the ON/OFF states of the power
semiconductor element 110. Here, the resistance 150 limits currents
input from the first terminal 104 side to the signal output section
134. For example, the resistance 150 operates as a protection
resistance to decrease the currents input from the first terminal
104 side to the signal output section 134 to a value equal to or
less than a predetermined current value even if a collector voltage
of the power semiconductor element 110 is raised to about 400V.
The resistance 160 is connected between the control terminal 102
and the gate terminal of the power semiconductor element 110. The
resistance 160 transmits the control signal to the gate terminal of
the power semiconductor element 110 if the cut-off circuit 120 is
in the OFF state. The resistance 160 drops the voltage of the
control signal if the cut-off circuit 120 causes the control signal
to flow to the reference potential in the ON state. That is, the
reference potential is to be supplied to the gate terminal of the
power semiconductor element 110.
The Zener diode 170 is connected between the resistance 150 and the
reference potential. The Zener diode 170 prevents an input of a
voltage exceeding a rated voltage of the signal output section 134
from the first terminal 104. For example, the Zener diode 170
clamps the voltage input from the first terminal 104 side to the
signal output section 134 to a predetermined voltage value even if
the collector voltage of the power semiconductor element 110 is
raised to about 400V. As one example, the Zener diode 170 clamps
the voltage to a range from about 6V to 16V.
In the semiconductor apparatus 100 according to the present
embodiment described above, as the control signal becomes the high
potential, the power semiconductor element 110 becomes the ON
state. Accordingly, a collector current Ic flows from the power
source 40 via the primary coil 32 of the ignition coil 30. Note
that a time change dIc/dt of the collector current Ic is determined
according to an inductance of the primary coil 32 and a supplied
voltage of the power source 40, and increases to a predetermined
(or set) current value. For example, the collector current Ic
increases to about several amperes, a dozen of amperes, or several
dozens of amperes.
Then, as the control signal becomes the low potential, the power
semiconductor element 110 becomes the OFF state and the collector
current drastically decreases. Due to the drastic decrease of the
collector current, a both-end voltage of the primary coil 32
drastically increases by a self-induction electromotive force and
an induced electromotive force up to about several dozens of kV is
generated on both ends of the secondary coil 34. The ignition
apparatus 1000 can cause the ignition plug 20 to discharge to
ignite the combustible gas by supplying such a voltage of the
secondary coil 34 to the ignition plug 20.
FIG. 2 shows a first example of operation waveforms of each section
of the semiconductor apparatus 100 according to the present
embodiment. In FIG. 2, the horizontal axis indicates time and the
vertical axis indicates voltage values or current values. Also,
FIG. 2 shows respective time waveforms, where "Vin" indicates the
control signal input from the control terminal 102, "Vt" indicates
the detection signal output by the detection section 132, "Vs"
indicates the cut-off circuit control signal output by the signal
output section 134, "Vg" indicates the potential of the gate
terminal of the power semiconductor element 110, "Ic" indicates the
currents (referred to as collector currents) between the collector
and the emitter of the power semiconductor element 110, and "Vc"
indicates the voltage (referred to as collector voltage) between
the collector and the emitter of the power semiconductor element
110.
FIG. 2 shows an example of a triangular wave shape, where the
control signal Vin input to the control terminal 102 linearly rises
from 0V to a voltage beyond the threshold Vthin of the detection
section 132, and after that, the control signal Vin linearly falls
down from the voltage beyond the threshold Vthin to 0V. Also, FIG.
2 shows the operation waveforms of each section with respect to the
control signal Vin of the triangular wave shape.
The detection section 132 may use the control signal input from the
control terminal 102 as an operation voltage. In this case, the
detection section 132 executes a detection operation in response to
the control signal beyond a threshold V1 being input. Therefore,
the detection section 132 becomes to output the input signal as it
is if the control signal does not exceed the threshold V1. That is,
the detection section 132 outputs a potential approximately the
same as the control signal Vin until the control signal Vin exceeds
the threshold V1. FIG. 2 shows an example where a detection signal
Vt of the detection section 132 becomes an output waveform
approximately the same as that of the control signal Vin until a
time t1 and after a time t4 is passed.
Also, in a case where Vin exceeds the threshold V1 and is a
potential equal to or less than the threshold Vthin, the detection
section 132 determines that the cut-off condition is satisfied and
outputs the low potential. FIG. 2 shows an example where the
detection signal Vt of the detection section 132 becomes the low
potential during a period from the time t1 to a time t2 and during
a period from a time t3 to a time t4. Also, in a case where Vin
exceeds the threshold Vthin, the detection section 132 determines
that the cut-off condition is not satisfied and outputs the high
potential. Note that the detection section 132 may output a
potential approximately the same as the control signal Vin as the
high potential. FIG. 2 shows an example where the detection signal
Vt of the detection section 132 becomes to have an output waveform
approximately the same as that of the control signal Vin during a
period from the time t2 to the time t3.
Since the signal output section 134 operates using the electrical
signal input from the first terminal 104 as the power source, when
outputting the high potential, the signal output section 134
outputs the potential of the smaller one of the collector voltage
Vc and a breakdown voltage Vzd of the Zener diode 170. For example,
if the detection signal Vt is the low potential, the signal output
section 134 outputs such a high potential as the inverted signal of
the low potential. FIG. 2 shows an example where the cut-off
circuit control signal Vs of the signal output section 134 outputs
the potential approximately the same as the breakdown voltage Vzd
until the time t2.
Also, the signal output section 134 outputs the low potential being
the inverted signal of the high potential in response to the
detection signal Vt becoming the high potential. FIG. 2 shows an
example where the cut-off circuit control signal Vs of the signal
output section 134 becomes the low potential during the period from
the time t2 to the time t3.
Note that during the period from the time t3 to the time t4, since
the detection signal Vt becomes the low potential, the signal
output section 134 outputs the high potential again. However, since
the control signal Vin is within a range of potentials larger than
a threshold Vthi of the power semiconductor element 110, the power
semiconductor element 110 is kept in the ON state and the collector
voltage Vc becomes a potential Vcl when the power semiconductor
element 110 is turned on. Since the potential Vcl becomes the
potential smaller than the breakdown voltage Vzd of the Zener diode
170, as shown in the example of FIG. 2, the cut-off circuit control
signal Vs of the signal output section 134 becomes to output the
potential approximately the same as the potential Vcl when the
collector terminal is turned on during the period from the time t3
to the time t4.
Also, the detection signal Vt becomes the low potential as the time
is beyond the time t4, and since the control signal Vin is within a
range of potentials smaller than the threshold Vthi of the power
semiconductor element 110, the power semiconductor element 110 is
switched to the OFF state and the collector voltage Vc becomes
approximately the same as the constant voltage Vb supplied by the
power source 40. Therefore, as shown in the example of FIG. 2, the
cut-off circuit control signal Vs of the signal output section 134
becomes the high potential approximately the same as the breakdown
voltage Vzd if the time is beyond the time t4.
The potential Vg of the gate terminal of the power semiconductor
element 110 becomes the low potential if the cut-off circuit
control signal Vs is the high potential exceeding the threshold of
the cut-off circuit 120. Also, the potential Vg becomes the
potential approximately the same as the control signal Vin if the
cut-off circuit control signal Vs is the low potential equal to or
less than the threshold of the cut-off circuit 120. FIG. 2 shows an
example where Vg becomes the low potential until the time t2 and
when the time is beyond the time t4, and becomes the potential
approximately the same as the control signal Vin during a period
from the time t2 to the time t4.
The power semiconductor element 110 operates according to such a
potential Vg of the gate terminal. That is, in the example of FIG.
2, the power semiconductor element 110 becomes the ON state during
the period from the time t2 to the time t4, and becomes the OFF
state during the period until the time t2 and the period beyond the
time t4.
That is, the collector current Ic of the power semiconductor
element 110 becomes approximate 0 (turned off) until Vg exceeds
Vthin, and flows (turned on) in response to Vg being in the
potential beyond Vthin, the maximum value of the potential being
(Vb-Vbi)/(R1+Ron). Here, Vb indicates a constant voltage supplied
by the power source 40, Vbi indicates a built-in potential of the
power semiconductor element 110, R1 indicates a resistance of the
primary coil 32, and Ron indicates an ON resistance of the power
semiconductor element 110. FIG. 2 shows an example where the
collector current Ic becomes OFF during the period until the time
t2 and during the period beyond the time t4, and becomes
(Vb-Vbi)/(R1+Ron) during the period from the time t2 to the time
t4.
The collector voltage Vc of the power semiconductor element 110
becomes the high potential until Vg exceeds Vthin and becomes the
low potential in response to Vg being the potential beyond Vthin.
FIG. 2 shows an example where Vc becomes the low potential at the
time t2 and becomes the high potential at the time t4.
Here, in the semiconductor apparatus 100 shown in FIG. 1, the
collector voltage Vc becomes approximately the same as the constant
voltage Vb supplied by the power source 40 in the state where the
power semiconductor element 110 is turned off. In this case, the
signal output section 134 outputs the potential approximately the
same as Vb, an upper limit of the potential being set to the
breakdown voltage of the Zener diode 170. Note that in a case where
Vb is larger than the threshold (1.1 V, as one example) of the
cut-off circuit 120, the cut-off circuit 120 cuts off the power
semiconductor element 110. In the present exemplary embodiment,
since the constant voltage Vb is 14V as one example, the collector
voltage Vc becomes the potential approximately the same as the
constant voltage Vb during the period until the time t2 and during
the period beyond the time t4.
Also, in the state where the power semiconductor element 110 is
turned on, the collector voltage Vc is determined according to Vb,
the built-in potential Vbi of the power semiconductor element 110,
the ON resistance Ron of the power semiconductor element 110, and
the resistance R1 of the primary coil 32, expressed as the
following equation: Vc=(Vb-Vbi).times.Ron/(Ron+R1)+Vbi. For
example, in a case where Vbi=0.6V, Ron=50 m.OMEGA., and
R1=0.6.OMEGA., if Vb=14V, Vc=1.63V, and if Vb=6V, Vc=1.02V.
That is, when the detection section 132 detects the cut-off
condition in the state where the power semiconductor element 110 is
turned on, if Vb=14V, the cut-off circuit 120 cuts off the power
semiconductor element 110, but if Vb=6V, the cut-off circuit 120
cannot cut off the power semiconductor element 110. In the present
exemplary embodiment, since the constant voltage Vb is 14V as one
example, the collector voltage Vc becomes the potential
approximately the same as Vc1=1.63V during the period from the time
t2 to the time t4.
As described above, it can been known that in the semiconductor
apparatus 100, during the period from the time t3 to the time t4,
the power semiconductor element 110 may remain in the ON state even
if the control signal Vin satisfies the cut-off condition in some
cases. As such a malfunction occurs and the operation is continued
in a state where the malfunction remains, failures of the power
semiconductor element 110 and the like may occur in some cases.
Also, not only the failures of the power semiconductor element 110
and the like, but also defects and the like of the internal
combustion engine and the like connected to the power semiconductor
element 110 may occur in some cases.
Note that as the threshold Vthi becomes further smaller, the power
semiconductor element 110 also reduces loss and becomes
advantageous as a switch; therefore, it is opposite to the
occurrence of the malfunction. Here, the semiconductor apparatus
200 according to the present embodiment surely cuts off the power
semiconductor element 110 to prevent the malfunction in response to
the control signal Vin satisfying the cut-off condition even if the
power semiconductor element 110 is turned on, without depending on
the value of the threshold Vthi.
FIG. 3 shows an exemplary configuration of the ignition apparatus
2000 according to the present embodiment. In the ignition apparatus
2000 shown in FIG. 3, operations approximately the same as those of
the ignition apparatus 2000 according to the present embodiment
shown in FIG. 1 are given with the same reference signs, and the
descriptions for them are omitted. The ignition apparatus 2000
comprises a semiconductor apparatus 200. The descriptions for the
control signal generation section 10, the ignition plug 20, the
ignition coil 30, and the power source 40 comprised in the ignition
apparatus 2000 are omitted.
The semiconductor apparatus 200 comprises a control terminal 202, a
first terminal 204, a second terminal 206, the power semiconductor
element 110, the cut-off circuit 120, the cut-off condition
detection section 130, the resistance 150, the resistance 160, the
Zener diode 170, a first rectifying element 210, and a second
rectifying element 220.
The control terminal 202 inputs a control signal which controls the
power semiconductor element 110. The control terminal 202 is
connected to the control signal generation section 10 and receives
the control signal. The first terminal 204 is connected to the
power source 40 via the ignition coil 30. The second terminal 206
is connected to the reference potential. That is, the first
terminal 204 is a terminal on the high-potential side compared to
the second terminal 206, and the second terminal 206 is a terminal
on the low-potential side compared to the first terminal 204.
Since the power semiconductor element 110, the cut-off circuit 120,
the resistance 150, the resistance 160, and the Zener diode 170
have been described in FIG. 1, the descriptions for them are
omitted here.
The cut-off condition detection section 130 has an input terminal
140 connected to the first terminal 204 and the control terminal
202 and uses an electrical signal input from the input terminal 140
as the power source. That is, the cut-off condition detection
section 130 uses two-system signals, which are the electrical
signal from the first terminal 204 and the control signal from the
control terminal 202, as the power source. Accordingly, the signal
output section 134 can compensate the voltage with the signal
voltage of the electrical signal from the control terminal 202 when
the signal voltage of the electrical signal from the first terminal
204 is lowered, being able to receive a stable power source voltage
from the input terminal 140.
The first rectifying element 210 is connected between the control
terminal 202 and the input terminal 140 of the cut-off condition
detection section 130. The first rectifying element 210 suppresses
the electrical signal flowing reversely to the control terminal 202
while supplying the control signal input from the control terminal
202 to the signal output section 134. Accordingly, the signal
output section 134 receives the power supply from the control
terminal 202 via the first rectifying element 210, the control
terminal 202 inputting the control signal which controls the power
semiconductor element 110. For example, in a case where the high
potential about 5V as the control signal is input from the control
terminal 202, the first rectifying element 210 supplies the
potential about 4.4V to the signal output section 134. Here, a
threshold Vf of the first rectifying element 210 is set to about
0.6V. As one example, the first rectifying element 210 is a
diode.
The second rectifying element 220 is connected between the first
terminal 204 and the input terminal 140 of the cut-off condition
detection section 130. The second rectifying element 220 may be
connected between the resistance 150 and the signal output section
134, and suppresses the electrical signal flowing reversely to the
first terminal 204 while supplying the potential of the first
terminal 204 to the signal output section 134 via the resistance
150. Accordingly, the signal output section 134 receives the power
supply from the first terminal 204 via the second rectifying
element 220.
For example, in a case where the breakdown voltage Vzd of the Zener
diode 170 is about 6V, the second rectifying element 220 supplies
the potential of about 5.4V to the signal output section 134 under
a condition where the collector voltage Vc is equal to or greater
than 6V. Here, the threshold Vf of the second rectifying element
220 is set to about 0.6V. As one example, the second rectifying
element 220 is a diode.
In this case, the resistance 150 is connected between the first
terminal 204 and the second rectifying element 220. It is
sufficient if the resistance 150 is an element having a resistance
limiting currents input from the first terminal 104 side to the
signal output section 134 via the input terminal 140, and the
resistance 150 is not limited to a resistor element.
Similar to the semiconductor apparatus 100 described in FIG. 1, in
the semiconductor apparatus 200 according to the present embodiment
described above, the power semiconductor element 110 becomes the ON
state if the control signal becomes the high potential.
Accordingly, as described in FIG. 1, the ignition apparatus 2000
can cause the ignition plug 20 to discharge to ignite the
combustible gas.
Also, in case where the control signal changes from the high
potential to the low potential, the signal output section 134
outputs the potential of about 4.4V first and then starts to cut
off the power semiconductor element 110. After the cutting off
starts, as Vc>Vin, the output potential of the signal output
section 134 becomes Vc-Vf and continues cutting off the power
semiconductor element 110. That is, since either the control
terminal 202 or the collector voltage is equal to or greater than
the high potential, the signal output section 134 can prevent the
malfunction of the power semiconductor element 110 without any
shortage of the power source voltage. Details for each section of
such an ignition apparatus 2000 will be described in the
followings.
FIG. 4 shows an exemplary configuration of a detection section 132
according to the present embodiment. The detection section 132
includes a control signal input section 302, a detection signal
output section 304, a reference potential input section 306, a
resistance 310, a resistance 320, an inverter 330, and an inverter
340.
The control signal input section 302 inputs the control signal
input from the control terminal 202. The detection section 132
operates using the control signal as the power source. The
detection signal output section 304 outputs the detection result of
the detection section 132. As one example, the detection signal
output section 304 is connected to the signal output section 134
and outputs the same logic potential as the control signal as the
detection result of the control signal. The reference potential
input section 306 is connected to the reference potential.
The resistance 310 and the resistance 320 are connected in series
between the control signal input section 302 and the reference
potential input section 306, and divide the voltage of the control
signal Vin input from the control signal input section 302. Here,
the voltage-divided potential divided and output by the resistance
310 and the resistance 320 is the potential between the resistance
310 and the resistance 320. For example, the voltage-divided
potential becomes: VinR2/(R1+R2), where R1 indicates the resistance
value of the resistance 310 and R2 indicates the resistance value
of the resistance 320. As one example, if the control signal
transiently rises linearly from the OFF potential (0V, as one
example) to the ON potential (5V, as one example), the
voltage-divided potential also rises linearly from 0V to
5R2/(R1+R2).
The inverter 330 having an input terminal connected between the
resistance 310 and the resistance 320 receives the voltage-divided
potential and outputs, from an output terminal, a signal where the
logic is inverted. The inverter 340 receives the output signal of
the inverter 330 and outputs a signal where the logic is
inverted.
Note that the inverter 330 and the inverter 340 respectively take
the control signal input from the control signal input section 302
as the operation power source. Therefore, in a process where the
control signal rises transiently, each inverter outputs the signal
of approximately the same potential as the control signal until the
control signal reaches the thresholds of the inverters. Note that
in the present example, the thresholds of each inverter are set to
approximately the same value V1. Operations in each section of such
a detection section 132 are described using FIG. 5.
FIG. 5 shows one example of operation waveforms of each section of
the detection section 132 according to the present embodiment. In
FIG. 5, the horizontal axis indicates time and the vertical axis
indicates output potentials. FIG. 5 shows one example of the output
potentials of the inverter 330 and the inverter 340 with respect to
a case where the control signal Vin input to the control signal
input section 302 linearly rises from the OFF potential (0V) to the
ON potential (5V). An output potential Vout1 of the inverter 330
and an output potential Vout2 of the inverter 340 are approximately
the same potential as the power source potential (i.e., the control
signal Vin) until the input potential reaches the threshold V1 of
the inverters.
In the inverter 330, since the input voltage-divided potential
VinR2/(R1+R2) is a value equal to or less than the threshold V1
even if the potential of the power source exceeds the threshold V1,
the input potential becomes the low potential and the inverted
output becomes the high potential. Note that even though the
inverter 330 operates so as to output the high potential, if the
power source potential is a transient potential in the process
until reaching the high potential (for example, 5V), the inverter
330 outputs the power source potential as the high potential. FIG.
5 shows an example where the output potential Vout1 of the inverter
330 outputs approximately the same potential as the power source
potential Vin on and after the time t1.
The inverter 330 inverts the low potential and outputs the inverted
potential in response to the potential of the power source
exceeding the threshold V1 and the input voltage-divided potential
exceeding the threshold V1 (i.e., the input of the high potential).
FIG. 5 shows an example where the output potential Vout1 of the
inverter 330 becomes the low potential (0V) at the time t2.
The inverter 340 inverts the low potential and outputs the inverted
potential in response to the potential of the power source being
the potential exceeding the threshold V1 and the input potential
being the potential exceeding the threshold V1. FIG. 5 shows an
example where the output potential Vout2 of the inverter 340
becomes the low potential at the time t1. The inverter 340 inverts
the high potential and outputs the inverted potential in response
to the potential of the power source being the potential exceeding
the threshold V1 and the input potential being the low potential.
Note that the inverter 340 outputs the power source potential as
the high potential in a case where the power source potential is
the transient potential in the process until reaching the high
potential. FIG. 5 shows an example where the output potential Vout2
of the inverter 340 becomes the potential approximately the same as
the power source potential Vin after the time t2 is passed.
The detection section 132 outputs such an output potential Vout2 of
the inverter 340 from the detection signal output section 304 as
the detection signal. Then, the signal output section 134 uses the
electrical signal input from the first terminal 204 and the control
terminal 202 as the power source and controls the cut-off circuit
120 according to the detection signal. Accordingly, the
semiconductor apparatus 200 according to the present embodiment
operates as an igniter to control the currents flowing through the
ignition coil 30 according to the control signal from outside.
Operations of the semiconductor apparatus 200 are described using
FIG. 6.
FIG. 6 shows examples of operation waveforms of each section of the
semiconductor apparatus 200 according to the present embodiment. In
FIG. 6, the horizontal axis indicates time and the vertical axis
indicates voltage values or current values. Also, FIG. 6 shows
respective time waveforms, where "Vin" indicates the control signal
input from the control terminal 202, "Vt" indicates the detection
signal output by the detection section 132, "Vs" indicates the
cut-off circuit control signal output by the signal output section
134, "Vg" indicates the potential of the gate terminal of the power
semiconductor element 110, "Ic" indicates the currents (referred to
as collector currents) between the collector and the emitter of the
power semiconductor element 110, and "Vc" indicates the voltage
(referred to as collector voltage) between the collector and the
emitter of the power semiconductor element 110.
The time waveform of the detection signal Vt of the detection
section 132 is approximately the same as that of the output
potential Vout2 of the inverter 340 described in FIG. 5. Also,
since the time waveform of the detection signal Vt of the detection
section 132 is also approximately the same as that of Vt of the
detection section 132 of the semiconductor apparatus 100 shown in
FIG. 2, the description for it is omitted here.
Since the signal output section 134 inverts the detection signal Vt
and outputs the inverted signal, the signal output section 134
operates so as to output the high potential until the time t2. In
this case, as described in FIG. 2, the potential input from the
first terminal 204 to the input terminal 140 becomes a potential
which is obtained by subtracting the threshold Vf of the second
rectifying element 220 from a potential of the smaller one of the
collector voltage Vc of the power semiconductor element 110 and the
breakdown voltage Vzd of the Zener diode 170. That is, because the
power semiconductor element 110 is in the OFF state, the potential
becomes Vzd-Vf until the time t2. Therefore, since the potential
Vzd-Vf is input as the power source voltage, similar to FIG. 2, the
signal output section 134 outputs the cut-off circuit control
signal Vs approximately the same as the potential Vzd-Vf.
Also, as the time t2 is passed, the signal output section 134
outputs the low potential as the inverted output of the detection
signal Vt. Also, as the time t3 is passed, the signal output
section 134 operates so as to output the high potential as the
inverted output of the detection signal Vt. In this case, during a
period since the time t3 is passed until the potential of the
control signal Vin becomes equal to or less than Vthi, as described
in FIG. 2, the potential input from the first terminal 204 to the
input terminal 140 becomes the potential approximately the same as
the potential Vcl when the collector terminal is turned on. On the
other hand, the potential of the control signal Vin input from the
control terminal 202 to the input terminal 140 is the potential
which is beyond Vthi.
Therefore, since the signal output section 134 of the present
embodiment uses the control signal Vin as the power source, the
signal output section 134 can output the cut-off circuit control
signal Vs being the high potential of the inverted output in
response to the detection signal Vt becoming the low potential at
the time t3. Accordingly, since the cut-off circuit 120 sets the
gate of the power semiconductor element 110 to the OFF potential,
the power semiconductor element 110 becomes the OFF state and the
collector voltage becomes Vb. That is, since the potential input
from the first terminal 204 to the input terminal 140 becomes
Vzd-Vf, the signal output section 134 can output the cut-off
circuit control signal Vs approximately the same as the potential
Vzd-Vf since the time t3.
As described above, as shown in the example of FIG. 6, the cut-off
circuit control signal Vs output by the signal output section 134
becomes the high potential until the time t2 and after the time t3
is passed, and becomes the low potential during the period from the
time t2 to the time t3. Since the cut-off circuit 120 controls the
gate potential Vg of the power semiconductor element 110 according
to such a cut-off circuit control signal Vs, as shown in the
example of FIG. 6, the gate potential Vg becomes approximately the
same potential as the control signal Vin during the period from the
time t2 to the time t3 and becomes the low potential until the time
t2 and after the time t3 is passed.
Therefore, the power semiconductor element 110 becomes the ON state
during the period from the time t2 to the time t3, and becomes the
OFF state until the time t2 and after the time t3 is passed.
Accordingly, as shown in the example of FIG. 6, the collector
current Ic is off until the time t2 and is on in response to Vg
being in the potential beyond Vthin, the maximum value of the
potential being (Vb-Vbi)/(R1+Ron).
Also, the collector voltage Vc of the power semiconductor element
110 becomes the high potential until the time t2 and after the time
t3 is passed, and becomes the low potential during the period from
the time t2 to the time t3. FIG. 6 shows an example where the
collector voltage Vc becomes the low potential (Vcl) during the
period from the time t2 to the time t3, and becomes the high
potential (Vb) during until the time t2 and after the time t3 is
passed.
The semiconductor apparatus 200 according to the present embodiment
described above can cut off the power semiconductor element 110 by
using the two-system power sources even if the control signal Vin
is switched from on to off. Therefore, the semiconductor apparatus
200 can surely cut off the power semiconductor device and can
prevent the malfunction according to the cut-off signal.
The example where the resistance 150 is connected between the first
terminal 204 and the second rectifying element 220 in the
semiconductor apparatus 200 according to the present embodiment
described above has been described. Instead of this, for example, a
switch element may be connected between the first terminal 204 and
the second rectifying element 220. FIG. 7 shows a first
modification example of the ignition apparatus 2000 according to
the present embodiment. In the ignition apparatus 2000 of the
present modification example, operations approximately the same as
those of the ignition apparatus 2000 according to the present
embodiment shown in FIG. 3 are given with the same reference signs,
and the descriptions for them are omitted.
An example is shown, where a switch element 350 is connected
between the first terminal 204 and the second rectifying element
220 in the ignition apparatus 2000 of the present modification
example. As one example, the switch element 350 may be a depression
type MOSFET, and in this case, a drain, a source, and a gate may be
respectively connected to the first terminal 204, the second
rectifying element 220, and the source. Accordingly, even if the
collector voltage Vc is excessive, the switch element 350 can
increase the resistance value between the drain and the source
corresponding to the collector voltage Vc. That is, the switch
element 350 can limit the current flowing through the second
rectifying element 220 to about 100 .mu.A as one example, and can
prevent the excessive current from flowing along with the increase
of the collector voltage Vc.
As described above, although it has been described that the
semiconductor apparatus 200 according to the present embodiment can
cut off the power semiconductor element 110, in addition to this,
the semiconductor apparatus 200 may further shorten the transient
cut-off time. In order to describe such a semiconductor apparatus
200, a transient response of the semiconductor apparatus 100
according to the present embodiment shown in FIG. 1 will be
described first.
FIG. 8 shows a second example of the operation waveforms of each
section of the semiconductor apparatus 100 according to the present
embodiment. In FIG. 8, the horizontal axis indicates time, and the
vertical axis indicates voltage values or current values. Also,
FIG. 8 shows respective time waveforms, where "Vin" indicates the
control signal input from the control terminal 102, "Vt" indicates
the detection signal output by the detection section 132, "Vs"
indicates the cut-off circuit control signal output by the signal
output section 134, "Vg" indicates the potential of the gate
terminal of the power semiconductor element 110, "Ic" indicates the
collector current of the power semiconductor element 110, and "Vc"
indicates the collector voltage of the power semiconductor element
110.
FIG. 8 shows an example of a rectangular wave shape, where the
control signal Vin becomes on at a time t5 and becomes off at a
time t7. Note that an amplitude value of the rectangular wave is
set to the voltage beyond the threshold Vthin of the detection
section 132. Accordingly, the detection signal Vt output by the
detection section 132 also becomes the rectangular wave shape where
the detection signal Vt becomes the high potential at the time t5
and becomes the low potential at the time t7.
According to such a detection signal Vt of the detection section
132, the cut-off circuit control signal Vs becomes the high
potential until the time t5, becomes the low potential during a
period from the time t5 to the time t7, and becomes the high
potential since the time t7. Therefore, the gate potential Vg of
the power semiconductor element 110 becomes the rectangular wave
shape where the gate potential Vg becomes the high potential at the
time t5 and becomes the low potential at the time t7. Accordingly,
the collector current Ic starts to flow at the time t5 and the
collector current Ic saturates at a time t6, as one example.
Similar to such a collector current Ic, the collector voltage Vc
starts to increase since the time t5 and reaches the potential Vcl
when the power semiconductor element 110 is turned on at the time
t6.
Then, at the time t7, since the gate potential Vg becomes the low
potential and the power semiconductor element 110 is switched to
OFF, the collector current Ic is cut off and the collector voltage
Vc becomes equal to the voltage Vb of the power source 40 after
drastically increasing. Such a transient operation of the
semiconductor apparatus 100 will be described in the
followings.
FIG. 9 shows one example of an enlarged waveform of the second
example of the operation waveform shown in FIG. 8. FIG. 9 shows an
example where a period of time before and after the control signal
Vin is switched to OFF in FIG. 8 is magnified by about 100 times.
In FIG. 9, a time when the control signal Vin becomes OFF is set as
a time t7a anew. The detection signal Vt output by the detection
section 132 becomes the low potential at the time t7a according to
the control signal Vin.
Transiently, as the control signal Vin becomes OFF, the gate
potential Vg of the power semiconductor element 110 is gradually
lowered as shown in a period from the time t7a to a time t7b. Since
the decreased amount of the gate potential Vg is slight, the
cut-off circuit control signal Vs, the collector current Ic, and
the collector voltage Vc almost have no change and maintain the
values at the time t7a during the period from the time t7a to the
time t7b.
As the gate potential Vg of the power semiconductor element 110 is
lowered, the power semiconductor element 110 is finally pinched
off. In this case, the collector voltage Vc starts to increase, the
mirror current flows from the collector to the gate, and the
decrease of the gate potential Vg is stopped. In FIG. 9, a period
when the gate potential Vg is maintained in an approximately
constant voltage is set as a period from the time t7b to a time
t7c. During the period from the time t7b to the time t7c, the
cut-off circuit control signal Vs starts to increase along with the
increase of the collector voltage Vc. Also, the collector current
Ic almost has no change and is maintained in the value at the time
t7a.
Then, as the collector voltage Vc of the power semiconductor
element 110 increases and reaches a fixed value, an expansion of a
depletion layer between the gate and the collector is stopped and
the mirror current is also stopped. Accordingly, the gate potential
Vg of the power semiconductor element 110 is lowered until reaching
0V. In FIG. 9, a period when the gate potential Vg is lowered to
the threshold Vthi is set as a period from the time t7c to a time
t7d. Along with such a decrease of the gate potential Vg, the
cut-off circuit control signal Vs and the collector voltage Vc
increase and the collector current Ic decreases.
As the gate potential Vg of the power semiconductor element 110
becomes 0V, the cut-off circuit control signal Vs, the collector
current Ic, and the collector voltage Vc, after drastically
increasing, respectively becomes equal to the voltage Vzd, OA, and
the voltage Vb. As described above, in the semiconductor apparatus
100, transiently, the gate potential Vg becomes smaller than the
threshold Vthi since the cut-off time from the time t7a when the
control signal Vin becomes OFF to the time t7d elapses. Here, the
semiconductor apparatus 200 according to the present embodiment
shortens such a cut-off time.
FIG. 10 shows a second modification example of the ignition
apparatus 2000 according to the present embodiment. In the ignition
apparatus 2000 of the second modification example, operations
approximately the same as those of the ignition apparatus 2000
according to the present embodiment shown in FIG. 3 are given with
the same reference signs, and the descriptions for them are
omitted. An example is shown in the semiconductor apparatus 200 of
the second modification example, where the input terminal 140 of
the cut-off condition detection section 130 is connected to the
first terminal 204 and the gate terminal of the power semiconductor
element 110, and connected to the control terminal 202 via a
resistive element.
That is, similar to the example of FIG. 3, in the semiconductor
apparatus 200, the input terminal 140 is connected to the first
terminal 204 via the second rectifying element 220 and the
resistance 150. Also, the input terminal 140 is connected to the
gate terminal of the power semiconductor element 110 via the first
rectifying element 210. Also, the input terminal 140 is connected
to the control terminal 202 via the first rectifying element 210
and the resistive element. That is, the first rectifying element
210 is connected between the resistive element and the input
terminal 140; also, the first rectifying element 210 is connected
between the gate terminal of the power semiconductor element 110
and the input terminal 140. Note that the resistive element is a
resistance or a switch element. FIG. 10 shows an example where the
resistive element is the resistance 160.
In this way, in the ignition apparatus 2000 of the second
modification example, a resistance value between the gate terminal
of the power semiconductor element 110 and the input terminal 140
becomes lower compared to a resistance value between the control
terminal 202 and the input terminal 140. Therefore, in a case where
the voltage of the control terminal 202 becomes 0V and the charges,
which are transiently charged by the gate, and the mirror current
flow from the gate terminal to the control terminal 202, the
potential of the input terminal 140 of the semiconductor apparatus
200 becomes higher by an amount of the voltage drop of the
resistance 160, compared to the semiconductor apparatus 100 shown
in FIG. 1.
That is, even if the collector voltage Vc of the power
semiconductor element 110 is a low voltage about Vc1 and the
voltage of the control terminal 202 becomes 0V, according to the
flow of the mirror current, the signal output section 134 can
receive the power source voltage corresponding to the voltage drop
of the resistance 160 from the input terminal 140. In this case,
the signal output section 134 can output the voltage in accordance
with the resistance value of the resistance 160 as the cut-off
circuit control signal Vs. A transient response of the
semiconductor apparatus 200 of such a second modification example
will be described in the followings.
FIG. 11 shows one example of the operation waveforms of each
section of the semiconductor apparatus 200 of the second
modification example. FIG. 11 shows one example of the operation
waveforms in a case where the control signal Vin shown in the
operation waveforms shown in FIG. 8 is input to the control
terminal 202. Note that the horizontal axis and the vertical axis
in FIG. 11 are shown by approximately the same scale as the
horizontal axis and the vertical axis of the operation waveforms
shown in FIG. 9.
That is, in FIG. 11, the horizontal axis indicates time and the
vertical axis indicates voltage values or current values. Also,
FIG. 11 shows respective time waveforms, where "Vin" indicates the
control signal input from the control terminal 202, "Vt" indicates
the detection signal output by the detection section 132, "Vs"
indicates the cut-off circuit control signal output by the signal
output section 134, "Vg" indicates the potential of the gate
terminal of the power semiconductor element 110, "Ic" indicates the
collector current of the power semiconductor element 110, and "Vc"
indicates the collector voltage of the power semiconductor element
110.
In FIG. 11, the time when the control signal Vin becomes OFF is set
as t7a. The detection signal Vt output by the detection section 132
becomes the low potential at the time t7a according to the control
signal Vin. As the control signal Vin becomes OFF, the gate
potential Vg of the power semiconductor element 110 is gradually
lowered as shown in a period from the time t7a to a time t7b'.
Here, the potential of the input terminal 140 becomes higher than
the potential (i.e., 0V) of the control terminal 202 by the amount
of the voltage drop of the resistance 160. Therefore, during the
period from the time t7a to the time t7b', the cut-off circuit
control signal Vs can be set to a voltage value larger than the
control signal Vs during the period from the time t7a to the time
t7b shown in FIG. 9. Specifically, the semiconductor apparatus 200
can set the cut-off circuit control signal Vs during the period
from the time t7a to the time t7b' larger than a threshold Vths of
the cut-off circuit 120 according to the setting of the resistance
value of the resistance 160. Accordingly, since the cut-off circuit
120 becomes the ON state, the speed at which the gate potential Vg
decreases becomes faster than the decrease speed of the gate
potential Vg shown in FIG. 9. That is, the time t7b' when the power
semiconductor element 110 is pinched off becomes an early time
compared to the time t7b.
Similar to the example of FIG. 9, as the power semiconductor
element 110 is pinched off and the collector voltage Vc increases,
the mirror current flows from the collector to the gate and the
decrease of the gate potential Vg is stopped. in FIG. 11, a period
when the gate potential Vg is maintained in an approximately
constant voltage is set as a period from the time t7b' to a time
t7c'. During the period from the time t7b' to the time t7c', since
the cut-off circuit control signal Vs can be kept in a state larger
than the threshold Vths, the cut-off circuit 120 can be maintained
in the ON state.
Accordingly, the amount of the mirror current flowing from the gate
of the power semiconductor element 110 via the cut-off circuit 120
can be larger and the increase speed of the collector voltage Vc
can be set faster than the increase speed of the collector voltage
Vc shown in FIG. 9. That is, the period until the mirror current of
the power semiconductor element 110 is stopped (the period from the
time t7b' to the time t7c') becomes shorter compared to the period
from the time t7b to the time t7c shown in FIG. 9.
As the mirror current of the power semiconductor element 110 is
stopped, the gate potential Vg is lowered until reaching 0V. in
FIG. 11, a period when the gate potential Vg is lowered to the
threshold Vthi is set as a period from the time t7c' to a time
t7d'. Along with such a decrease of the gate potential Vg, the
cut-off circuit control signal Vs and the collector voltage Vc
increase and the collector current Ic decreases. As the gate
potential Vg of the power semiconductor element 110 becomes 0V,
similar to the example of FIG. 9, the cut-off circuit control
signal Vs, the collector current Ic, and the collector voltage Vc,
after drastically increasing, respectively become equal to the
voltage Vzd, 0 A, and the voltage Vb.
As described above, the semiconductor apparatus 200 can set the
gate potential Vg smaller than the threshold Vthi at the time t7d'
which is earlier than the time t7d. That is, since the
semiconductor apparatus 200 of the second modification example can
set the period from the time t7a to the time t7c' shorter compared
to the period from the time t7a to the time t7c of the
semiconductor apparatus 100 shown in FIG. 9, the cut-off time can
be shortened.
FIG. 12 shows a third modification example of the ignition
apparatus 2000 according to the present embodiment. In the ignition
apparatus 2000 of the third modification example, operations
approximately the same as those of the ignition apparatus 2000
according to the second modification example shown in FIG. 11 are
given with the same reference signs, and the descriptions for them
are omitted. The ignition apparatus 2000 according to the third
modification example further includes a delay circuit 230.
The delay circuit 230 is provided between the cut-off condition
detection section 130 and the cut-off circuit 120 to delay a signal
transmitted to the cut-off circuit 120 by the cut-off condition
detection section 130. The delay circuit 230 may have a resistive
element and a capacitive element. Also, the delay circuit 230 may
have an inductance element and a capacitive element. The delay
circuit 230 may be a filter circuit and the like to lower a high
frequency component of a noise and the like. FIG. 12 shows an
example where the delay circuit 230 has a resistance 232 and a
capacitor 234.
In this case, the delay circuit 230 delays a signal passing through
the delay circuit 230 by a delay time determined in response to a
resistance value of the resistance 232 and a capacitance value of
the capacitor 234. That is, the cut-off circuit control signal Vs
output from the signal output section 134 of the cut-off condition
detection section 130 is delayed by the delay circuit 230 and then
input into the cut-off circuit 120. Accordingly, in a case where
the power semiconductor element 110 is in the ON state, even if the
cut-off circuit control signal Vs output from the signal output
section 134 temporarily becomes the high potential, as the cut-off
circuit control signal Vs becomes the low potential in a shorter
time than the delay time, the power semiconductor element 110 can
be prevented from being switched to the OFF state.
For example, a malfunction of the cut-off condition detection
section 130 may occur due to a noise and the like and the cut-off
circuit control signal Vs may suddenly become the high potential in
some cases. In such a case, according to the ignition apparatus
2000 of the third modification example, if the cut-off circuit
control signal Vs returns back to the low potential in a shorter
time than the delay time, the malfunction of the power
semiconductor element 110 can be prevented. A transient response of
such an ignition apparatus 2000 of the third modification example
is described next.
FIG. 13 shows one example of operation waveforms of each section of
the semiconductor apparatus 200 of the third modification example.
Similar to FIG. 11, FIG. 13 shows one example of operation
waveforms in a case where the control signal Vin shown in the
operation waveforms shown in FIG. 8 is input into the control
terminal 202. Note that it is assumed that the horizontal axis and
the vertical axis of FIG. 13 are shown in approximately the same
scale as that of the horizontal axis and the vertical axis of the
operation waveforms shown in FIG. 9.
That is, the horizontal axis of FIG. 13 refers to time and the
vertical axis of FIG. 13 refers to voltage values or current
values. Also, FIG. 13 shows respective time waveforms, where "Vin"
indicates the control signal input from the control terminal 202,
"Vt" indicates the detection signal output by the detection section
132, "Vs" indicates the cut-off circuit control signal output by
the signal output section 134, "Vs'" indicates the cut-off circuit
control signal input into the gate of the cut-off circuit 120, "Vg"
indicates the potential of the gate terminal of the power
semiconductor element 110, "Ic" indicates the collector currents of
the power semiconductor element 110, and "Vc" indicates the
collector voltage of the power semiconductor element 110.
In FIG. 13, a time at which the control signal Vin becomes OFF is
set as t7a. The detection signal Vt output by the detection section
132 becomes the low potential at the time t7a in response to the
control signal Vin. The cut-off circuit control signal Vs output by
the signal output section 134 becomes the high potential in
response to the control signal Vin becoming OFF. Here, since the
delay circuit 230 has been provided between the signal output
section 134 and the cut-off circuit 120, the cut-off circuit
control signal Vs' input into the gate of the cut-off circuit 120
is gradually increased in response to a time constant determined by
the resistance 232 and the capacitor 234.
Then, at a time t7a', as the cut-off circuit control signal Vs'
input into the gate of the cut-off circuit 120 reaches a threshold
Vths of the cut-off circuit 120, the cut-off circuit 120 transits
to the ON state. In response to the cut-off circuit 120 transiting
to the ON state, the gate potential Vg of the power semiconductor
element 110 is gradually decreased during a period from the time
t7a' to a time t7b''. Note that the time t7b'' may be approximately
the same time as a time delayed from the time t7b' shown in FIG. 11
by the delay time of the delay circuit 230. Similarly, each of a
time t7c'' and a time t7d'' shown in FIG. 13 may be approximately
the same time as a time delayed from each of the time t7c' and the
time t7d' shown in FIG. 11 by the delay time of the delay circuit
230.
Also, since the semiconductor apparatus 200 of the third
modification example is a configuration where the delay circuit 230
is added to the semiconductor apparatus 200 of the second
modification example, the operation waveforms of each section after
the time t7b'' becomes the operation waveforms similar to the
operation waveforms of each section after the time t7b' shown in
FIG. 11. Note that the cut-off circuit control signal Vs' input
into the gate of the cut-off circuit 120 becomes a waveform where
the cut-off circuit control signal Vs output by the signal output
section 134 is delayed in response to the time constant. Also, the
cut-off circuit control signal Vs of FIG. 13 shows an example where
the high frequency signal is removed through a filtering effect
according to the delay circuit 230, compared to the cut-off circuit
control signal Vs of FIG. 12.
As described above, by adding the delay circuit 230, the
semiconductor apparatus 200 of the third modification example can
prevent the malfunction of the power semiconductor element 110 from
occurring even if the noise having a pulse width shorter than the
delay time is mixed into the cut-off circuit control signal Vs
while executing the operations approximately similar to the
operations of the semiconductor apparatus 200 of the second
modification example.
While the embodiments of the present invention have been described,
the technical scope of the invention is not limited to the above
described embodiments. It is apparent to persons skilled in the art
that various alterations and improvements can be added to the
above-described embodiments. It is also apparent from the scope of
the claims that the embodiments added with such alterations or
improvements can be included in the technical scope of the
invention.
The operations, procedures, steps, and stages of each process
performed by an apparatus, system, program, and method shown in the
claims, embodiments, or diagrams can be performed in any order as
long as the order is not indicated by "prior to," "before," or the
like and as long as the output from a previous process is not used
in a later process. Even if the process flow is described using
phrases such as "first" or "next" in the claims, embodiments, or
diagrams, it does not necessarily mean that the process must be
performed in this order.
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